A couple of hours ago I got together with some buddies of mine who are also musicians. I was telling them about your claim and about Jerremy's post. My one friend who is a keyboardist is also an engineer at a local studio in the Cleveland area, and he basically said that it would have been virtually impossible for him to have properly done an accurate match up of the vocals, he would have had to have gone in and piece by piece after piece removed everything from both recordings with the exception of the lead vocals, but including everything like crowd noise.
It took me about 2 minutes to sync up "Seperate Ways" from Manchester with that song from Vegas.
When you load audio into recording software, you can see the waveform, and it's not hard to sync up two versions of the same song by lining them up at a clear visual point in the audio (i.e. when the drums come in at the beginning of "Seperate Ways").
Since the band is playing to a click track, every night's version of each song will be
exactly the same tempo, making it very easy.
The Manchester audience recording is very good, and the vocals are very clear, it's not necessary to try to isolate them.
No, I don't participate in bootlegging. Sorry. I believe in respecting the artists wishes--but that is another topic.
If it's good enough to pipe over P.A. speakers in front of a paying crowd, it's good enough to be recorded and listened to. I'm against the selling of bootlegs, which allows someone to make a profit off of music that's not theirs, but free trading and sharing of live recordings is a good thing (unless of course your band sucks live).